The ability to comprehensively address research questions related to successful weight gain prevention requires knowledge of both physiological and behavioral aspects of weight regulation. The primary objective of this K01 Career Development Award is to enable Dr. Davy to obtain advanced training in health behavior change so that she may build upon her background in nutrition and exercise physiology to develop innovative long-term, behavioral theory-based weight gain prevention interventions. Dr. Davy's long-term career goal is to develop an independent, successful, extramurally-funded research program focused upon the long-term prevention of weight gain. To achieve this goal, she has proposed to acquire knowledge and technical expertise in several areas: 1) the science and practice of theory-based health behavior change, 2) the use of advanced technology for health behavior change interventions, 3) dietary intake and physical activity assessment methodologies, 4) statistics and experimental design. The resources available to Dr. Davy at this institution and the combined experience of her mentoring team, which includes Drs. Donnelly, Hill, Most, Phillips, Rankin, and her primary mentor, Dr. Winett, ensure the proposed objectives can be met. A training plan of structured coursework, workshops, and site visits is integrated with a research plan that will enable Dr. Davy to acquire the knowledge and expertise identifed in her career development objectives. The Research Plan is focused upon "closing the energy gap" (eg, excess calories associated with the mean increase in body weight in our population) to prevent weight gain in college students at-risk for weight gain. The primary aim is to determine the efficacy of a long-term Internet-delivered weight gain prevention program in college students. We will employ a social cognitive theory (SCT)-based Internet intervention to "close the energy gap" by promoting small but sustainable changes in diet and physical activity habits. We will also determine the influence of potential mediators of weight gain prevention in this population, including dietary fat intake, fruit/vegetable consumption, physical activity habits, and behaviors related to self-regulation. A weight gain prevention approach could provide young adults with the skills to successfully manage their weight long-term. If this Internet-delivered weight gain prevention approach is effective in this at-risk population, it could be modified to reach larger numbers of individuals in other populations.